# Narrow band-pass filter

1. Mar 3, 2006

### electronic engineer

I was aksed to study and draw the transitions of narrow band-pass filter function gives as :

Av(s)=Ao (s*Wo/Q)*(1/(s^2+s*Wo/Q+Wo^2) ; S Laplace transform

where: Wo is central frequency

Q quality factor Q=Wo/WH-WL=Wo/BW

WH &WL are high cut-off and low cut-off frequency respectively

just need some hits !

2. Mar 3, 2006

### Corneo

Whats your problem? Determine the center, upper, and lower cut off frequencies?

3. Mar 3, 2006

### Staff: Mentor

You can use Excel to plot it to get a feel for what it looks like, although it will plot best in log-log (log frequency on horizontal axis). Start with a Q=1 plot, then overlay Q=10 and Q=0.1 plots. Pick some generic Wo frequency for starters, like 100kHz or something.

What textbook are you using? Most texts should have a good discussion of the BPF transfer function and the effect of the Q factor. If your text is lacking, there are lots of resources on the web. I googled bandpass analog filter transfer function tutorial, and got lots of good hits. Here's one -- scroll down to some of the Filter Design articles:

http://www.circuitsage.com/filter.html [Broken]

Last edited by a moderator: May 2, 2017
4. Mar 3, 2006

### electronic engineer

oh ,berkeman thanks you for your googling , sometimes i google for various things but I find out that you have good experience in selecting keywords, is there any generic rule to precisely find what you need through google or that just depends on repitation?!

thanks a lot!

5. Mar 3, 2006

### Staff: Mentor

Mostly getting better at google involves trying out stuff, and learning some of the advanced features. Check out the advanced feature list sometime -- I forget if google supports the "near" keyword, for example. Only some search engines do. Using quotes around multiple word phrases helps a lot in cutting down on the extra search hits that are displayed. And using the + sign before required terms in the search also helps a lot sometimes.

Also, I've lately found the keywork "tutorial" to be real helpful in finding info in the form that helps folks here on PF.

6. Mar 4, 2006

### electronic engineer

I didnn't find that feature but there's another feature for finding pages similar to a webpage we detect , and find pages that link to the page!

Page-Specific Search:
Similar Find pages similar to the page